A history-of-music map: each conquest's territory, battles, campaign routes and — above all — its musical legacy were compiled editorially from public historical and musicological reference material (encyclopaedic sources, music-history scholarship on the spread of instruments, modes and repertoire).
Territories are approximate — coarse outlines of each power's maximum extent, drawn to convey reach, not exact borders. Battle and city coordinates are real.
Earth globe, terrain & depth-shaded oceans:
NASA Blue Marble (public domain) ↗ ·
NOAA ETOPO relief (public domain) ↗ (shared with
Visual Data Planet).
Sister maps:
the Visual Data hub ↗